Enode B and E-UTRAN

                                                       Enode B        

E-UTRAN Node B also known as Evolved Node B (eNodeB or eNB) is the element in E-UTRA of LTE is the evolution of the element Node B in UTRA of UMTS.it is a hardware that is connected with mobile phone network  which communicates directly with user equipments.. in eNB there is no separate controller element. It simplifies the architecture and allows lower response times. The

eNB uses the E-UTRA protocols OFDMA  for downlink and SCFDMA for uplink on its LTE interface.it has its own functionality rather than using an Radio Network Controller. It interfaces with the System Architecture Evolution core and uses S1_MME interface with the mobility management for control traffic.

                                       E-UTRAN

The E-UTRAN consists of eNODEBs which provide E-UTRA user plane and control plane (RRC ) protocol termination toward the user equipment. The eNBs are interconnected with each other by means of the X2 interface. The eNBs are also connected by means of the s1 interface to the evolved packet core (EPC).

FUNCTIONS WITHIN THE ACCESS STRATUM:

This provides the ability , infrastructure and accessibility to the UE in acquiring the capabilities and services of the network. The radio access protocols in the E-UTRAN access stratum are comprised of numerous functionalities:

1.   RRM performs radio bearer control, admission and connection mobility control and dynamic allocation of resources to UE’s in both uplink and downlink.

2.   Traffic management in conjuction with RRM supports real and non real time user traffic between UE and architecture side.

EVOLUTION TOWARDS 4G and LTE ECOSYSTEM

EVOLUTION TOWARDS 4G

Distributed base stations with remote radio head (RRH) capability greatly help mobile operators to resolve cost , performance, and efficiency challenges when deploying new base stations on the road to fully developed 4G networks. Multi mode radios capable of operating according to GSM,HSPA,LTE and WIMAX standards and advanced software configurability are the key features to develop a new network. The most recent OFDMA standards Wimax and LTE include 20 MHZ wideband radio channels for both time division duplex (TDD) and frequency division duplex (FDD).the throughput is enhanced by using MIMO antenna techniques.

LTE ECOSYSTEM

LTE  ecosystem report is given by Global Mobile Suppliers Association (GSA) . the most recent report is given on JULY 5,2013. This report provides an analysis of 948 LTE devices launched in the marlet by 100 suppliers. LTE is the fastest growing mobile technology ever.

948 LTE USER DEVICES—GSA monitors and serveys worldwide mobile broadband market developments and publishes the facts, statistics and trends in its “ Evolution to LTE” report, confirminh operaor commitments to LTE.

1800 mhz: most poplar LTE brand

This band continues to be the most popular spectrum for lte DEPLOYMENTS, USED IN THE MAJORITY OF COMMERCIALLY LAUNCHED NETWORKS GLOBALLY. All the most popular smartphones and brands support LTE 1800.

LTE TDD DEVICES

It is a single global 3GPP standard that addresses both TDD and FDD spectrum.LTE TDD is an integral part of the standard.Interest is strong and growing globally.

DEVICES ANALYSIS USING GAMBOD

GAMBOD is a GSA analyser for mobile broadband devices. It is a unique searching tool developed by GSA  for mobile broadband devices allowins searches for GSA databases for suppliers. Results are present in spreadsheets or charts.

ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS (OFDMA) - SINGLE-CARRIER FDMA (SC-FDMA)

ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS

It is a multi user version of digital modulation scheme.it works by assigning subsets of subcarriers to individual users.This technique has following advantages over CDMA:

1. It can combat multipath interference and it is less complex.
2. It can achieve a higher MIMO spectral efficiency.

Principle—  because of feedback information about the channel conditions, user to subcarrier assignment can be achieved. In this different number of subcarriers can be assigned to different users in view to support Quality of service that means to control data rate and error probability for each user.This is achieved by combining OFDM with time division multiple access. In this constant and shorter delay can be achieved. It is considered to be highly suitable for broadband wireless networks due to its advantagesincluding scalability and MIMO and it ability of channel frequency selectivity.It is used in Wimax and 3GPP LTE. High speed OFDM packet acess (HSOPA) now named as Evolved umts terrestrial radio access (E-UTRA).

  SINGLE-CARRIER FDMA (SC-FDMA)

It is a frequency- division multiple access scheme. It deals with the assignment of multiple users to a shared communication resorce.  It has drawn great attention as an attractive alternative to OFDMA. It has been adopted as the uplink multiple access scheme in 3GPP LTE or E-ULTRA ( evolved ultra). The major advantage of SC-FDMA is low PAPR (peak-to-average power ratio).

Transmission of SC-FDMA is very similar to OFDMA. In this, for each user the sequence of bits transmitted is mapped in symbols (BPSK,QPSK).

In SC-FDMA multiple access among users is made possible by assigning different users different set of sub carriers. The distinguishing feature  of SC-FDMA is that it leads to single carrier transmit signal in contrast to OFDMA which is multi carrier transmission scheme.

Advantages:

Low PAPR, low sensitivity to carrier frequency offset, greater robustness against spectra nulls, less sensitive to non linear distortion and hence, it allows the use of low cost power amplifiers.

4G systems - What is 4G LTE Technology

4G systems was originally visioned by Defence Advanced Research Projects Agency  (DARPA). The DARPA selected the distributed architecture and end to end internet protocol (IP). They believed in an early age, in peer to peer networking in which every mobile device would be both a transreceiver and a router for other devices in the network ,this eliminates the need of spoke and the hub which are the weakness of  2g and 3g cellular systems. 

The traditional voice calling is replaced by IP telephony in 4g systems. The  specifications of 4G named as International Mobile Technology Advanced (IMT-A) was proposed by International Telecommunication Union Radio (ITU-R). The main aim of developing this technology is  speed requirements of 100 mbps for high mobility such as users in trains and a speed of 1 gbps for stationary users. The basic idea behind 4G is to use only packet switching and internet protocol based communication. 

The spread spectrum technique which is used in 3G is replaced by OFDMA in order to achieve desired speed.In order to fulfill these requirements pre 4G was launched which are the technologies named as LTE and wimax. The 1st vision of 4g with ITU was laid in 2002.  In 2008, HTC announced first Wimax enable mobile as MAX 4G. Unfortunately, these technologies are not able to meet the requirements of 4g as desired. 

In feb 2007, NTT DOCOMO the japanese company tested 4g and was able to achieve maximum packet transmission at a rate of 5gbps.  LTE advanced offering a downloading speed of 1 gbps and uploading speed of 500 mbps. In April 2012, Bharti Airtel is the company which successfully launched 4G first time in India. In dec 2012, telcel launched 4G LTE in nine  major cities of Mexico.